 public class Example4_9 {

   public static void main(String args[]) {

       SIM simOne = new SIM(13889776509L);

       MobileTelephone mobile = new MobileTelephone();

       mobile.setSIM(simOne);

       System.out.println("手机号码:"+mobile.lookNumber()); 

       SIM simTwo = new SIM(15967563567L);

       mobile.setSIM(simTwo);

       System.out.println("手机号码:"+mobile.lookNumber());  

    }

}
